33% increase in muzzle energy for like projectiles against barrel I/D is one thing, but in this case I am talking about the potential energy loss past a viscous liquid seal versus the main air stream down the barrel.

When the bolt is in the retracted position behind the air inlet (about 90% of the duty cycle) the path of least resistance is forward.

I see your point, still, how about wiping off the gun oil and wrapping it in masking tape until it's a tight fit, just to attempt to quantify the difference?